Prosthetic heart valves are either mechanical or of the type which include commissure supports and valve leaflets. Mechanical heart valves typically include a ball valve. The other type of heart valve typically includes a frame, valve leaflets mounted on the frame and a suture ring. The valve leaflets may be formed of either biological or synthetic material. This form of heart valve has commissure supports which project away from the suture ring and terminate in free end portions. Thus, each of the commissure supports forms a projection or strut. This invention relates to an assembly which includes a prosthetic heart valve of the type which has commissure supports and valve leaflets.
Prosthetic heart valves are commonly used to replace diseased valves within the human heart. In replacing a mitral valve, it is common practice for the physician to manually position the mitral valve and sew the suture ring to heart tissue using sutures and an appropriate suturing technique. Manual handling of the valve during valve replacement increases the danger of damaging the valve. In addition, the replacement valve must be properly oriented in the heart, and manual orientation and placement are difficult.
More importantly, however, damage to the left ventricle can result from mitral valve replacement, and this problem is discussed in Katske, Gordon M.D. et al, "Posterior Midventricular Rupture After Mitral Valve Replacement", The Annals Of Thoracic Surgery, Volume 27, No. 2, February 1979, and Nunez, L. M.D. et al, "Delayed Rupture Of The Left Ventricle After Mitral Valve Replacement With Bioprosthesis", The Annals Of Thoracic Surgery, Volume 27, No. 5, May, 1979. The consequences of ventricular rupture can, of course, be fatal. As reported by these authors, the damage to the left ventricle is believed to be the result of impalement of a strut or commissure support against the left ventricle.
Another serious problem with mitral valve replacement is suture looping, and this problem is referred to in the Katske et al publication referred to above. Suture looping means that the suture which is used to attach or mount the valve to the heart tissue is inadvertently wrapped around one or more of the commissure supports or struts. If this occurs, the looped suture interferes with valve operation.